The purpose of this study is to investigate the factors influencing the quality of life of patients with chronic obstructive pulmonary disease. The sample consisted of 94 outpatients. One questionnaire entitled ”RAND 36-item Health Survey” was used to measure the quality of life in this study. Data were analyzed by suing analysis of variance. The results showed that there were statistically significant differences in quality of life in terms of disease severity, as indicated by pulmonary function and activity level, age, marital status, and education. Religion and smoking history did not have effects on the quality of life. In conclusion of the results revealed that the qualities of life were most affected by pulmonary function and age. The physical functioning of quality of life was affected by disease severity, age, marital status, and education.